Arc welding electrode



June 3, 1947. F, 5001- 2,421,594

ARC WELDING ELECTRODES Filed Feb. 21, 1945 I/vveNTaIQ mmaw B M+ a MW Patente d June 3, 1947 PATENT OFFICE 2,421,594 I ARC WEDDING ELECTRODE RtibertlHenry Farmer Boot London, England, as-

. signer to Under Water Weldr's. & Repairers Limited, London, England, a British company Application renew 21, 1945, Serial No. 579,023

a In Great: Britain December 15, 1943 3'Glai'ms. (01. 219-8) This invention comprises improvements inv orrelatingto arc-welding electrodes.

It is an object of the invention to; provide; an arc-welding electrode suitable for use in welding beneath the surface of liguid as described in Unit'd'States'PatentNo. 2,408,175, September 24, 1946;

a In Welding; beneaththesurface of aqueous li uids as described in the aforesaid application it is essential to employ an electrode'which' is not only flux covered but in which the acces's'of water to the electrodebypenetration of'the flux coatm is 'preverited Most coating compounds which might-be supposed to keep water out of pentration into theflux} proveto be incapable of pro,- tecti'r'ig the electrode when it is immersed for a considerable time, especially in seawater, which being impregnated with sodium salts has a high osmotic pressure.

According to the present invention an arcweldingelectrode forthe purposedescribed corrsists -ofa metal core covered over its working surface with a layerofii-ux intimately admixed with a tough solid polymer of a vinyl. or substituted vinyl compound. Where the polymer is not of itself sufficiently tough (non-brittle) it may be rendered so by admixture with a suitable plasticiser.

The layer of flux which is: intimately mixed.

with the polymer may be in direct contact with the metal core of the electrode or, if desired, it may be disposed'cver an inner layer of flux not so admixed.

pne suitable polymer is; polyvinyl chloride (CHaCHCl) other vinyl or substituted vinyl compounds may beemployedsuch-as polymers of vinyl acetate (cnscgoon ono, methyl methacryla'te: (CI-Ii {Ql-lqlCOOCI-Ia) methyl. acrylate (CI-IzCI-TOOCHs) or styrene Preferably over the layer of flux which is intimately mixed with the polyvinyl chloride or other polymer is an outer skin consisting of such a polymer.

The invention includes a process of manufacture of an arc-welding electrode consisting in taking a solution of a tough solid soluble polymer of a vinyl or substituted vinyl compound in a volatile solvent, mixing this with a flux to a paste form, coating a metallic electrode with the paste and hardening by evaporation of the sol vent. After coating with the flux mixed with the polymer and hardening thereof the electrode may be dipped in a solution of such a polymer in a volatile solvent so as to cover the surface with an additional continuous layer of the polymer.

v 2 Alternatively an electrode according; to the invention may be made by taking a metallic "electrode, coatingit with a non-waterproof'porou's paste of aflux anddryiiig'and'thereafter appryingt'o the electrode a'solution of a tough solid solublepolymer'of' a vinyl or substituted vinyl compound in a volatilesolvent, the solution being so applied that with the aid of the solvent it penetrates intimately into at least the outer pores of the flux and formed, continuous skin thereover, and drying theicompbundby evaporation of: the solvent; The applicationo't the solution maybe effectedeither by dipping the electrode into the solution. or by painting: 'on'a lsuifici'entl'yi thick coat to -cause the solution; whil'e inliquidvform before the solvent has been dried out, to penetrate into the o'uterl'ayers of." the flux: and also to-iorm a continuouswaterproof ex'ternal'coating; II the compound is applied by spraying, this must be done by a sufficiently high pressure spray to ensure penetration "of the coating 1 into the pores of the flux beforeevaporation of the solvent.

In-the accompanyingdrawing: Figure l is a diagrammaticillustration cf-one-formof lec trode according to: the. invention andFigure-Q :is a similar view to an enlarged scale of a second Figure 1 a shows .a the: type ofelectrode hereinafter referred; to where the flux \Ilintimately mixed with the polymeris? in direct. contact with the-core I2.

Figure 2shows (partly in section) the-type int which-the core l 2-Tis covered-with a layer of flux l-3randfadmixedo with polymer and thereover isa layer oi mixed flux-z I 4 p The following is a description byway of exmeme 1 of, electrodes; manufactured in accordance with. the invention: and. of. the: process of; produc= tion J thereof H Example I 1 Polyvinyl chloride (CH2=CHC1) of a nonbrittle soluble grade is taken and dissolved in xylene or toluene so as to produce a solution consisting of solvent and 15% polyvinyl chlo The quantity of solution of polyvinyl chloride and powdered flux is such that an easily workable paste is produced and the electrode is coated with this paste by dipping or extrusion. The extrusion may be done in any ordinary electrode coating apparatus and the coating, on an electrode of the diameter of say five thirty-seconds of an inch, may be of a thickness of one sixteenth of an inch. After the application of the flux the solvent is dried off and the result is a hard impervious flux layer.

After drying the surface is coated with a layer of the polyvinyl chloride applied by dipping the electrode in a solution made up as follows:

Per cent Polyvinyl chloride A plasticiser consisting of equal parts of dibutyl phthalate and tricresyl phosphate 5 Benzene or toluene 80 The total quantity of polyvinyl chloride and plasticiser in the completed coating of the electrode may be of the order of to reckoned on the weight of the flux present.

The result is an electrode coated with a hard impervious flux layer which will not deteriorate or permit electrolysis at the metal surface of the core even if it is immersed in water fo a long time.

Example II If the compound is painted on an adequate quantity must be employed to penetrate intimately at least into the outer pores of the flux and, if the compound is applied by dipping the electrode must be kept in the solution for a sumcient time to ensure intimate penetration. Upon drying the coating of polyvinyl compound not only forms an intimately adherent layer where it is mixed with a flux, which layer overlies an inner layer of flux not admixed with the polyvinyl compound, but in addition there is a skin of the polyvinyl compound on the outer surfac of the electrode which is continuous and water-resistant. The properties of the electrode from the users point of view are similar to what has already been described in connection with Example I hereof.

Example III In this case instead of using polyvinyl chloride, polymerised methyl methacrylate is employed. Methyl methacrylate is a substituted vinyl derivative, having the hydrogen in the vinyl radical substituted by a CH3 group, and of the following formula CH2=C(CH3) COOCHa A suitable commercial form of this body i that sold, already mixed with plasticiser and some solvent, under the trade nam Welvic. This solution is of a treacly consistency and further solvent (benzene or toluene or xylene) is added to thin the solution to the consistency of an easily flowing liquid, when the composition will be approximately as follows:

V Per cent Methyl methacrylate 15 Plasticiser 5 Solvent Electrodes, already coated with flux of the 00111-5 position set forth in Example I, are dipped in this solution, allowed to soak for about fifteen minutes, removed and dried.

I claim:

1. All arc-welding electrode consisting of a steel core covered over its working surface with a layer of flux and over the flux a continuous outer skin of a tough solid polymer selected from the class consisting of vinyl and substituted vinyl compounds, the layer of polymer being intimatelymixed with the flux at the interface be-:;

tween the two layers.

2. An arc-Welding electrode as claimed claim 1, wherein the polymer is polyvinyl chloride.

, 3. An arc-welding electrode as claimed in claim 1, wherein the polymer is methyl-methacrylate.

ROBERT HENRY FARMER Boo'r.

REFERENCES CITED .The following references are of recordinthe file of this patent: V

' UNITEDSTATES PATENTS".

Number Name 7 1,324,227 Carpenter Dec. 9, 1919 1,354,476 Fay Oct. 5,1920 1,871,257 Cadwell Aug. 9, 1932 1,931,466 Notvest IOct. 17, 1933 1,954,394 Meisse Apr. 10, 1934 1,998,947 Weed Apr. 23, 1935' 2,158,984 Lytle et a1 May 16, 1939 

